At the time, he already had a girlfriend — his now-wife Priscilla Chan — and he was obsessed with the internet. Google was great for searching for news and Wikipedia was great for searching for reference material, but there was a gap.

“There was no tool where you could go and learn about other people. I didn’t know how to build that so instead I started building little tools,” Zuckerberg told Döpfner.

He built a small tool called Coursematch where people could list what classes they were taking. He did build the Facematch tool, as seen in “The Social Network”, but that was just a prank, he says.

Instead, the roots of Facebook go back to a college kid spending too much time programming and not enough time paying attention in class. Here’s how Zuckerberg turned a study tool into a social network, and why no one else did it.

Mathias Döpfner: But how did [Coursematch] become Facebook?

Mark Zuckerberg: For the final the class — called the “Rome of Augustus”, it was an art history class — there were all theses pieces of art in the class and they were going to show you a handful and you would need to write an essay about the historical significance of that piece of art.

I hadn’t paid much attention in the class because I was programming other things so when it came time for the final I was like oh I am screwed, I don’t know any of this stuff.

So as a study tool I built a little service that showed you at random one of the pieces of art and let you enter what you thought was significant from an art history perspective. So I sent it out to the email list for the class and said hey I have a study tool, and everyone just filled in what is significant about all the pieces of art and it ended up being this great social study tool.

I think the grades on the test that year were higher than they had been in the past. So there were all these different projects, I probably did like 10 different things like this when I was at Harvard. I thought I should put some of this stuff together to create a tool where people can share whatever they want with the people around them. And that was how the first version of Facebook came.

Döpfner: How long did the development take?

Zuckerberg: It only took me two weeks to build the first version of Facebook because I had so much stuff before then.

Döpfner: And of course, you probably hadn’t the idea that this could transform into a three hundred billion dollar company?

Zuckerberg: No, not at all.

Döpfner: When did you sense that it could be really a big thing?

Zuckerberg: You know I actually remember very specifically the night that I launched Facebook at Harvard. I used to go out to get pizza with a friend who I did all my computer science homework with. And I remember talking to him and saying I am so happy we have this at Harvard because now our community can be connected but one day someone is going to build this for the world.

And I didn’t even think it might be us. It was not like, oh I hope we can turn this into something big. In my mind there was no way this is going to be us. It was going to be someone else we are just college students. When I look back on the last twelve years, what has been the most surprising it’s that no one else did it. And I ask myself, why no one else did it.

Döpfner: Why?

Zuckerberg: I just think it’s because there were all these little reasons not to do it. You know people at every step of the way said “Oh that’s just for young people” so they didn’t work on it as much as they could. Or, “Fine, a bunch of people are using it, but it will never make any money.” Or, “Oh it works in the US but it is not going to work around the world.” Or, “Oh it works but it is not going to work on mobile.” All these different reasons, you know how it is.